Influenza A (H1N1) Dr. Mohammad . B. Obeidat Royal Medical Services / King Hussain Medical City
<ul><li>Influenza A viruses categorized by subtype </li></ul><ul><li>according to two surface proteins….. </li></ul><ul><ul><ul><li>Hemagglutinin (H) – 16 known </li></ul></ul></ul><ul><ul><ul><ul><li>- Site of attachment to host cells </li></ul></ul></ul></ul><ul><ul><ul><ul><li>- Antibody to HA is protective </li></ul></ul></ul></ul><ul><ul><ul><li>Neuraminidase (N) – 9 known </li></ul></ul></ul><ul><ul><ul><ul><li>- Helps release virions from cells </li></ul></ul></ul></ul><ul><ul><ul><ul><li>- Antibody to NA can help modify disease severity </li></ul></ul></ul></ul>N H
A novel influenza A (H1N1) virus of swine origin emerged among people in Mexico during the spring of 2009 and spread with travellers worldwide, resulting in the first influenza pandemic since 1968. As of October 2009, 195 countries have reported confirmed human cases of pandemic (H1N1) 2009. While the majority of illnesses caused by pandemic (H1N1) 2009 virus infection have been self-limited mild-to-moderate uncomplicated disease, severe complications including fatal outcomes have been reported.
The pandemic (H1N1) 2009 influenza virus differs in its pathogenicity from seasonalinfluenza in two key aspects. First, as the majority of human population has little or no pre-existing immunity to the virus, the impact of the infection has been in a wider age range, in particular among children and young adults. Secondly, the virus can infect the lower respiratory tract and cause rapidly progressive pneumonia especially in children and young to middle-aged adults.
EPIDEMIOLOGY <ul><li>Incubation period- 1-7 days </li></ul><ul><li>Transmission </li></ul><ul><li>PRIMARY CASE –direct contact with pigs </li></ul><ul><li>SECONDARY CASES </li></ul><ul><li>sneezing, coughing , resp droplets, body fluids(diarroeal stool) contact surfaces </li></ul>
CLINICAL FEATURES Vomiting or diarrhea (not typical for influenza but reported by recent cases of swine influenza infection)
<ul><li>Approximately 10-30% of hospitalized patients in some countries have required admission to intensive care units (ICU). </li></ul><ul><li>Critically ill patients include those who experienced rapidly progressive lower respiratory tract disease, respiratory failure, andacute respiratory distress syndrome (ARDS) with refractory hypoxemia. </li></ul><ul><li>Other severe complications have included secondary invasive bacterial infection, septic shock, renalfailure, multiple organ dysfunction, myocarditis, encephalitis, and worsening of underlying chronic disease conditions such as asthma, chronic obstructive pulmonary disease (COPD), or congestive cardiac failure. </li></ul>
Risk factors for severe disease • Infants and young children, in particular <2 years • Pregnant women • Persons of any age with chronic pulmonary disease (e.g. asthma, COPD) • Persons of any age with chronic cardiac disease (e.g. congestive cardiac failure) • Persons with metabolic disorders (e.g. diabetes) • Persons with chronic renal disease, chronic hepatic disease, certain neurological conditions (including neuromuscular, neurocognitive, and seizure disorders) • Persons aged 65 years and older
Case description Uncomplicated influenza • ILI symptoms include: fever, cough, sore throat, rhinorrhea,headache, muscle pain, and malaise, but no shortness of breath and no dyspnoea. Patients may present with some or all of these symptoms. • Gastrointestinal illness may also be present, such as diarrhoea and/or vomiting, especially in children, but without evidence of dehydration.
Complicated or severe influenza • Presenting clinical (e.g. shortness of breath/dyspnoea, tachypnea, hypoxia) and/or radiological signs of lower respiratory tract disease (e.g. pneumonia), central nervous system (CNS) involvement (e.g. encephalopathy, encephalitis), severe dehydration, orpresenting secondary complications, such as renal failure, multiorgan failure, and septic shock. Other complications can include rhabdomyolysis and myocarditis. • Exacerbation of underlying chronic disease, including asthma, COPD, chronic hepatic or renal failure,diabetes, or other cardiovascular conditions. • Any other condition or clinical presentation requiring hospital admission for clinical management.
Signs and symptoms of progressive disease Patients who present initially with uncomplicated influenza may progress to more severe disease. Progression can be rapid (i.e. within 24 hours). The following are some of the indicators of progression, which would necessitate an urgent review of patient management: • Symptoms and signs suggesting oxygen impairment or cardiopulmonary insufficiency: - Shortness of breath (with activity or at rest), difficulty in breathing2, turning blue, bloody or coloured sputum, chest pain, and low blood pressure; - Hypoxia, as indicated by pulse oximetry.
<ul><li>Symptoms and signs suggesting CNS complications: </li></ul><ul><li>Altered mental status, unconsciousness, drowsiness, or difficult to awaken and recurring or persistent convulsions (seizures), confusion, severe weakness, or paralysis. </li></ul><ul><li>Evidence of sustained virus replication or invasive secondary bacterial infection based on laboratory testing or clinical signs (e.g. persistent high fever and other symptoms beyond 3 days). </li></ul><ul><li>Severe dehydration, manifested as decreased activity, dizziness, decreased urine output, and lethargy </li></ul>
General treatment considerations To date, most people with pandemic (H1N1) 2009 virus infection have had self-limiting uncomplicated illness. Supportive care can be provided as needed, such as antipyretics (e.g. paracetamol or acetaminophen) for fever or pain and fluid rehydration. Patients with suspected pandemic (H1N1) 2009 virus infection, including patients presenting with uncomplicated illness, should be given information and guidance on signs for deterioration of illness and instructed on how to seek immediate medical attention
Pregnant women, especially those with co-morbidities, are at increased risk for complications from influenza virus infection. Influenza in pregnancy is associated with an increased risk of adverse pregnancy outcomes, such as spontaneous abortion, preterm birth, and fetal distress. Consequently, pregnant women with suspected or confirmed pandemic (H1N1) 2009 virus infection warrant closer observation and early antiviral treatment Paracetamol (acetaminophen) is recommended to ease fever and pain in pregnant women,
<ul><li>Antiviral therapy </li></ul><ul><li>The following is a summary of treatment recommendations: </li></ul><ul><li>Patients who have severe or progressive clinical illness should be treated with oseltamivir. Treatment should be initiated as soon as possible. </li></ul><ul><li>This recommendation applies to all patient groups, including pregnant women, and young children <2 years, including neonates. </li></ul><ul><li>In patients with severe or progressive illness not responding to normal treatment regimens, higher doses of oseltamivir and longer duration of treatment may be appropriate. </li></ul><ul><li>In adults, a dose of 150 mg twice daily is being used in some situations. </li></ul>
• Patients at higher risk of developing severe or complicated illness, but presenting with uncomplicated illness due to influenza virus infection, should be treated with oseltamivir. Treatment should be initiated as soon as possible following onset of illness. • Patients not considered to be at higher risk of developing severe or complicated illness and who have uncomplicated illness due to confirmed or strongly suspected influenza virus infection need not be treated with antivirals.
Objectives : To assess the epidemiological, clinical manifestations and prognosis of H1N1 influenza in prince rashid military hospital
Methods : In a retrospective study review of all patients whom admitted in Prince Rashed Military Hospital, North of Jordan, from 16 October to 21 November 2009, with a proven diagnosis of H1N1 influenza “A”. Only patients with a positive polymerase chain reaction nasopharyngeal swab were included, and excluded when the swab was negative.
<ul><li>A total of 32 patients with proven H1N1 infection were admitted, </li></ul><ul><li>Female patients 17 (53.1%) and males 15 (46.9%). </li></ul><ul><li>The mean age was 29.1 years (standard deviation; 10.8 years), and </li></ul><ul><li>the median age was 28.5 years. </li></ul><ul><li>The most common symptoms in order of frequency were; </li></ul><ul><li>fever 30 (93.8%), </li></ul><ul><li>cough 27 (84.4%), </li></ul><ul><li>sore throat 17 (53.1%), </li></ul><ul><li>headache 6 (18.8%), </li></ul><ul><li>shortness of breath 5 (15.6%), </li></ul><ul><li>myalgia 4 (12.5%), </li></ul><ul><li>diarrhea 3 (9.4%) , </li></ul>
<ul><li>vomiting 2 (6.3%). </li></ul><ul><li>Average duration of symptoms before admission +/- standard deviation was 2.1+/- 1.2 days, </li></ul><ul><li>and time of hospitalization was 2.9 +/- 1.1 days. </li></ul><ul><li>Full recovery was obtained in 30 patients (93.8%). </li></ul><ul><li>Death occurred in 2 patients (6.3%). </li></ul>
Conclusion : Pandemic H1N1 influenza A, has reached North of Jordan and poses a risk to the young population without immunity, and those with co-morbid disease, particularly of the lungs, and the pregnant.